▎ 摘　　要

Strain-induced band-gap deformations of hydrogenated/fluorinated graphene and hexagonal BN sheets have been investigated from first principles using density functional calculations. Within the harmonic approximation, the deformation is found to be higher for hydrogenated systems than for fluorinated systems. Interestingly, our calculated band-gap deformations for hydrogenated/fluorinated graphene and BN sheets are positive, while that for a pristine BN sheet is found to be negative. This is due to the strong overlap between nearest-neighbor pi orbitals in the pristine BN sheet, which is absent in the passivated systems. We also estimate the intrinsic strength of these materials under a harmonic uniaxial strain, and find that the in-plane stiffnesses of fluorinated and hydrogenated graphene are close, but larger in magnitude compared to those of a fluorinated and hydrogenated BN sheet.